Stewartville, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.1 °F (low) to 53.9 °F (high). Annual precipitation averages 34.8 Inches. Stewartville is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.2 °F | 22.6 °F | 0.94 in. |
| February | 9.9 °F | 27.0 °F | 1.02 in. |
| March | 22.1 °F | 39.4 °F | 1.82 in. |
| April | 34.4 °F | 54.7 °F | 3.55 in. |
| May | 46.6 °F | 67.2 °F | 4.53 in. |
| June | 57.1 °F | 77.1 °F | 5.52 in. |
| July | 60.5 °F | 80.5 °F | 4.32 in. |
| August | 58.1 °F | 78.3 °F | 4.21 in. |
| September | 49.8 °F | 71.8 °F | 3.57 in. |
| October | 37.4 °F | 58.3 °F | 2.48 in. |
| November | 25.3 °F | 41.9 °F | 1.65 in. |
| December | 13.5 °F | 28.3 °F | 1.23 in. |
| Annual | 35.1 °F | 53.9 °F | 34.84 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |